Folding brake



Dec. 7, 1943. o. G. LILJA 2,336,105

FOLDING BRAKE Filed June 24, 1940 3 Sheets-Sheet J a .25. 1 4 I I H 9 j 25' g H 5 f6 if 2+ I? if I Q 9 l Il 33 3! Li a; 1! i 2a 29 I0 I 0- 01 a gigs .16

Dec. 7, 1943. 0; G. LIL JA 2,336,105

FOLDING BRAKE Filed June 24, 1940 s Sheets-Sheet I6 is .97 if 73 7; 43 111 6 5, 6

Patented Dec. 7, 1943 UNITED STATES PATENT OFFICE FOLDING BRAKE Oscar G. Lilja, Rockford, Ill.

Application June 24, 1940, Serial No. 342,116

8 Claims. (Cl. 153-16) This invention relates to bending machines and particularly to sheet metal bending machines of the so-called brake-type such as are commonly used in sheet metal shops for the purpose of bending relatively thin section sheet metal.

The difiiculty with these devices in the past has been the limitation in their ability to bend the metal through much more than the right angle. So far as I am aware, none of these machines have been capable of bending the metal back upon itself in the manner required for the production of a satisfactory sheet metal fold. The common practice has been to bend the edge portion of the metal through slightly more than 90 by means of the brake, and to thereafter manually hammer the edge portion down to bend it through substantially 180.

An important object of the invention is the provision of a folding brake capable of bending the metal through substantially 180 so as to complete the full bend with a single operation.

A further object of the invention is the provision of a brake-type bending device in which the upper bending form is retractable, and wherein means are provided for retracting this member after the bend has been partially formed to permit the completion of the bending in a single operation.

A still further object of the invention is the provision of a bending brake in which the sheet metal is rigidly held in position during the bending operation, and wherein latch means serve to hold the apron in position through a substantial portion of the bending operation and is released toward the end of the bend for the purpose of permitting the return of the apron to inoperation position.

A further object of the invention is the provision of a brake wherein the apron is supported in a novel fashion, and additional means are provided for holding the metal in place.

Other objects and advantages will appear from the following description and the accompanying drawings, in which- Figure 1 is a side elevation of a brake embodying my'invention showing the apron and apron frame in the open position;

Fig. 2 is a section on the line 2-2 of Figure 1, showing the parts in the same position, a sheet of metal being positioned on the table and bed in position for the start of the bending operation;

Fig. 3 is a section on the line 33 of Figure 1 showing the apron and frame in the lower bending position;

Fig. 4 is a section similar to Fig. 2 showing the parts in the third step of the bending operation, the metal being bent through somewhat more than and substantially at the start of the tripping operation;

Fig. 5 is a view similar to Fig. 2 showing the parts in the positions occupied thereby at the conclusion of the bending operation, the edge portion of the metal being bent through substantially and the apron being retracted to its inoperative position;

Fig. 6 is a section on the line 6- 6 of Fig. 4, and

Fig. 7 is a section on the line 7-l of Fig. 4.

The embodiment of the invention herein described has a supporting frame or tail comprising legs at Op osite ends thereof designated generally by the numerals 8 and 9, and top and side rails I l and [2 at the back side and ends thereof. Other conventional frame members, such as shown at l3, are provided as required, to give rigidity to the table. Positioned at the ends of the supporting structure above the legs 8 and 9 are end plates 14 and 15 formed of heavy section cast metal as best shown in Figs. 1 and 3. These end plates are connected at the rear by a channel iron member l6 for the purpose of rigidly interconnecting the end plates. The end plates and the channel iron member [6 are fastened to the top of the supporting table in any well known manner, as, for example, by bolting or welding so as to be fixedly supported thereon. Flanges l1 and I8 are provided adjacent the forward edges of the plates l4 and I5 and project laterally therefrom, as best shown in Figs. 1 and 3, these flanges being provided with internally threaded holes l9, and with a forwardly disposed lug 2 I provided with an internally threaded opening carrying a threaded screw 22. Positioned against the flanges 11 and I3 and spanning the distance between the plates to and I5 is a bed designated generally by the numeral 23 in the form of a relatively thick plate. This plate is provided adjacent each end with elongated openings 24 for the reception of screws 25 and 26 adapted to engage in the threaded openings [9 to retain the bed in position. The elongated openings 24permit of adjustment of the elevation of the bed by action of the screws 22 s that the position of the upper edge of the plate can be adjusted and the screws 25 and 26 drawn tight in order to accommodate the brake to metals of relativeiy great thickness. Positioned on th upper edge of the member l5 and extending forwardly to the bed 23 is a table 27, the table having support on the member l6 and on the bed, the upper surface thereof being flush with the upper end of the bed plate 23, as

I J ii e a' -Q and for assisting in by' ean of a erase-sarisrefineries t'o' iplates'b y 'screwsBl Fig.1 3

; same 'to rotate'onfthefap sc E ach'of the guide 'platesilias best shown in Fig. 2. The table 21 terminates short of the end plates I4 and I5, as will be seen from Fig. 3, to provide space through which various operating elements may pass, as will presently be described.

The forward edge of the end plates I4 and 15 has bosses 23 and 29 adapted to support pivot members 3i and 32 (Figure 1) for rotation on a horizontal axis by means of pivot pins passing through the bosses 2'8 and 29 and through. ears 33 on the pivot member 3| and ears 34 on the pivot member 32. These pivot members form the end portions of a bending leaf designated geherally by the numeral 35 which has a bending plate 36 attached at its ends to the pivot iii'eriibers 3i and 32 by means of screws 37 and 3 8 passing through elongated openings. 39 and Min he plate 36 and threaded "into'o'p'e'nirigs'i'n the pivot members. The pivot members have 'lia'terally disposed flanges 42 carrying screws 53 adaptedtoadjust the positio of. thejplate 36 on the pivot members, as wors -a parenti em Fig, 3. The bending leaf is '50 arranged that f edgeof the bending plate 36 is normailyeoplanar with the upper. 1 edge, of {the ,bed pla'tef23 in the manner shown "in Fig. ajwherepy these "plates, together with the table '21, function tdj support apiece of sheet metal asshowrfat i forthepfirpose of bending the sameinlthe g enieial rnanner of a conventional brake. T ed e o th ela e' fiefi th r-ed of thel eaf 36 are" Substantially I1 the." cn'te'r. line 7 t m pivots onfwhic'h'thed aftiifn soithat when the leaf, is rotated throngn' 139, the leaf will rest substantially mtnessinepnneas the bed, as shownf in" Fig. 5 .For 'thefpur'poseof 'bd' plate 23 and the bendi g le I plates are each. provided fidin'gilongifi 'tact withthe'metal.

rigidly interconnect? the two p v u per forward a saint? .1

'whihii giia nei action of thesp'rin'gs 85 and he grooves 62 between the positions shown in Figs.- 2, 3 and 4 and the position shown in Fig. 5, the apron being normally biased to the position shown in Fig. 5 by means of springs 65 having one end anchored to the apron by means of screws 61, and the opposite end anchored to the crossbar 59 as shown at 68 (Figs. 2 and 5).

The apron is moved from its inoperative or retraoted position as shown in Fig. 5 to its operativeposition as shown in Figs. 2-4 by means of spaced levers 69 and H pinned to a cross shaft 12, which shaft has pivotal support in ears E3 on the guide plates 56. The levers 69 and H are .connected by means of links 74 to upstanding- "bos'ss 15 on the upper surface of the apron so that by'rotating the levers to the position shown ,.in. Fig. 2 the apron is moved from the position "of'Fi'gfB"to"the"'position of Fig. 2. The apron is heldfin the operative position of Figs. 2-4 by means ofi a latch having alatoh bar 16 (Figs. 3, dl provided with a hooked end having an ting s cr ew "Qfidaptedl'to engage over the was; with? w on Shown in F and the 'latchb'ars being pivotally supported on'the shoul- ..der fhvmeaiis i.,j ps r. ws. e i .l e'd' t he en a ed e ii n b means, of p i y jIJhescirewsflfl serve to'g'permit' adjustment of he'operativef position of the' apron fordifiers ll ss q a efwi h eac elea'si'ng dog is pivotally ng normallyfnrge'd'to ig, Kby meahs of the Se d gs "ha e a end ar '35} are provided 9 be'engaged'by v. H ,n affasb [sh nEmma-1.4 ji rlthenu hos of eas apro "when p, the bending] operation proceeds to the required point. 'Thescrews 84'areadjustable seas adjust the point at which the apron will be'fvith raw h 3D? DQ3313 '5. i m fi fj e n. the 9 heen n se' .ans th 9f -i an bee r s t bn -5 2 ss js tas hed 0 ba s. 8 ends'br the, shoulders ESfand .(Eie:,.. L eie rao i r ed I h str n fi "ing'c'arriedbn lugs 81 attached to the baclg'fside 9? t e. fl es ai l idl T s f flp movement is li ed by levers 88; andi'SQ lpiivotally .i upnorfiedbn p of cap screw tween memen e Tc'au'se ithe posed arms 94 plvotaliy supportedthe sho ers 64 b .me .e p z. ee w ii 'i bar b'eing'ur'ged to "rotate in a clockwise direction 2,336,105 "aboutthe cap screws 95 by action of springs 96 acting between the ends of the arms 94 and the bar 59. The extent of this rotary motion is limited by stops 9'! carried in the bar 59 and adjustable so as to vary the amount of this rotation under the action of the springs 96, the stops bearing against the arms 94. Thus, when the apron frame is brought to the position shown in Figs. 3 and 4, the beveled surface 98 of the pressure bar 93 first engages the work, and upon continued rotation of the frame, the beveled face 99 of the apron is brought into contact with the work, this continued movement causing stressing of the spring 98.

In operation, the sheet metal to be bent, such as that shown at 44, is placed on the table 2'! With the parts in the position shown in Figs. 1 and 2, the point where the bend is tooccur being placed at the junction between the bed and the bending leaf. Thereafter the levers 88 and 89 are brought to the upper position as shown in Fig. 3, bringing the pressure bar as and the apron 65 into contact with the metal. Thereafter the bars 46 and 4'! are grasped by the operator and the bending leaf moved to the position shown in Fig. 5. During this operation the parts will pass through the position shown in Fig. i. In other words, when the outer surface of the bending leaf contacts the screws 84, the dogs 79 will be rotated, causing the latch bars 15 to release the ends of the apron and allowing the apron to move up to the position shown in Fig. 5. It will be seen that this occurs after the edge of the metal has been bent through slightly more than 90 as shown at Hil in Fig. 4. The apron having been withdrawn from beneath the folded edge portion of the metal, continued movement of the bending leaf causes the edge portion to be folded back upon itself in the manner shown in Fig. 5. In order to further compact the folded portion, the leaf may be rotated back slightly, as, for example, to the position shown in Fig. 4, and released, whereupon it will be brought down against the folded portion with a hammer blow under the impact of the weights 53 and 5A.

An important advantage accruing from the structure shown in Figs. 1-7, inclusive, is the fact that a complete folding operation can be conducted on sheet metal with a single operation of the folding leaf. In other words, the metal is inserted in the manner of a conventional sheet metal brake, and by a single operation of the bending leaf a complete fold can be produced, as

distinguished from slightly more than a 90 bend, as has heretofore been possible. Another advantage of the construction lies in its ease of operation and the manner in which the apron is withdrawn during the bending operation. It will also be seen that I have provided improved means whereby the work is fixedly held in position during the bending operation.

It will be understood that the embodiment of the invention herein shown is by way of illustration and not limitation, and I do not wish to be limited except as required by the scope of the appended claims, in which I claim:

1. The combination in a folding brake of spaced end members, a bed extending between said end members for supporting a sheet of metal to be, bent, a bending leaf rotatable about one edge from a depending vertical position to an upstanding vertical position to bend said sheet,

a frame supported between said end members for rotation between a closed position engaging said sheet and an open position, means on said frame for engaging said sheet outside the bending area thereof to clamp said sheet against movement when the frame occupies the closed position, an apron positioned on said frame movable thereon between an operative position to engage said sheet at the bending area when said frame occupies said closed position and an inoperative position, manually operative means for moving said apron from inoperative to said operative position, spring means for moving said apron from said operative to said inoperative position, latch means for retaining said apron in said operative position, and means for releasing said latch at a predetermined point in the rotation of said leaf in response to rotation thereof for movement of said apron out of said operative position to withdraw said apron from the path of said leaf.

2. The combination in a folding brake of spaced end members, a bed extending between said end members for supporting a sheet of metal to be bent, a bending leaf rotatable to bend said sheet against said bed, a clamping frame movably supported on said end members for movement between a closed position engaging said sheet and an open position, holding means on said frame movable therewith for engaging said sheet outside the bending area thereof to clamp said sheet against movement when the frame occupies closed position, an apron positioned on said frame for movement thereon between an operative position to engage said sheet at the bending area when said frame occupies said closed position and an inoperative position, and means for moving said apron from said operative to said inoperative position in response to movement of said bending leaf through a predetermined part of its bending rotation.

3. The combination recited in claim 2 wherein said holding means includes means for engaging said sheet, spring means for urging the engaging means against the sheet when said frame occupies said closed position, and stop means for limiting the action of said spring means when said frame is moved to open position to lift said engagin means and release the sheet.

4. The combination in a folding brake of a bed for supporting a sheet of metal to be bent, a bending leaf rotatable to bend said sheet against said bed, an apron frame having spaced rotatable end plates each provided with a slide way, an apron having its ends positioned in said ways for sliding movement between operative and inoperative positions, means for rotating said frame to bring said apron into contact with the sheet on said bed when the apron occupies its operative position, and means responsive to movement of said bending leaf through an intermediate point of its rotation for moving said apron from said operative to said inoperative position out of contact with said sheet to withdraw said apron from the path of said leaf.

5. The combination recited in claim 4 wherein weight means is positioned on said bending leaf to resist rotation thereof during the first part of its movement and to assist rotation during the latter part of its movement to drive said leaf against the sheet on said bed and thereby facilitate the folding of the metal.

6. The combination in a folding brake of a bed for supporting a sheet of metal to be bent, a bending leaf rotatable to bend said sheet against said bed, clamping means for engaging said sheet outside the bending area thereof to clamp said sheet against mdvement kifi'rifig the bzidifig 6pexaltioh; an ap'rdn mbvable betwenandpftive "pbsitien' to ngeige said sheet .a rid a-Ttftdinelderati ve pesiti'cinj lt'ch 'rne'airis 6 1 "fetti nifig "the "apron in said operative positionfr-heriiflhig 6f the sheet thereagainst in respense tdfetaltien -f the-1e,f' through a, {part 'of I .a rdtati'r'l, ""siirirl'g "filelhs 'fdr urgingsaid api'0n t0 said 'ifiGpi atiVe "psit'ibh, and 'm'afis for releasing nieei-ns to move said a'pren hilt-0f the-operative "pOsitidn-sO that updn 'further i'dtatien ofthe' lef the shet-is bjentupendtselfto form a -fold.

'7. The eo'mbineltion 'in' a. folding-brake f-s'becd end mmbeis, a; bed extending between said end member's' fc'ar suppb'r-t-ing a sheet ofmeta1 to be Bent, 2, lai'r'ibihg frzime -OmpriSing el'a'f 'pifig r'rians for holding said-'- sheet infies'itibngaihst said bed, a nibv alble apron aainst wh ieh" said sheet isbent, and means fofmoVing-shidttubron ith respeet-to the remaihder-bf'the*Clatmping 7 me toffe'ta foldihg bperdtion, 'n'iegnsfor =siippo rtmg said elampizig fran'ie 1m said enjd rhnibers fer rotation with respect thef'eto and remq 'rel therefi'dm, inea'ns threw-on: sag-a -end members iositioned to bearagain'sfisai'd frme 1 to 'i'etete the sairie to pe'sitien' engaging? the sheet," and "a bn'ding leaf 'fotatable toberld'said shet against s -id apron and-siid bed.

BI The Combination in =a folding i brake 'of a i 5 stationary bed for s'ufiporting-a. sheet of metal to "bebeht; a bending leaf rotatable through-"about 180 t0 ber'id'Said-shet -tgainst said-'bed to forin a. Eli-clamping meansfor engaging salid 'sheet 'c'iut'sidethe bending-area thereof to "clan'dp said 10 shet a g'ain'st the bed to prevent movementof the sheet during the ben'ding eperation an apron 

